Posted on 10 November 20199 December 2021 by abmarineservice — 2 Comments

Starting problems? 3 tips to fix.

Here are some tips in the event that you have a battery-related problem or a malfunction in the starting system.

If the engine of your boat has little or no power to start, the starter motor or battery may be defective.First things first: make sure that you have checked the following before you start looking at replacing these parts. Several other things, such as a corroded main fuse, mass switch or soiled electrical connections and poorly connected wiring, may be the cause of a starting problem.

Make sure you are safe before you start working.The engine should only run through the starter motor without starting, so turn off the fuel supply. This can easily be done by using the stop solenoid or by putting the throttle in the stop position. Let’s get the multimeter out and do some testing!

1. Battery check in a few steps!

Step 1: A full battery; set the multimeter to DC (direct current) voltage, connect the red probe to the positive and then the black probe to the negative battery terminal. If the multimeter indicates that the battery output is less than 12 volts, first charge or replace the battery before we continue. At 12.4 volts, the battery is fully charged. Double that figure (24.8 volts) for a 24-volt battery. A few millivolts more or less is okay.

Step 2: Put the multimeter back on Direct Current. Connect the red wire of the multimeter to the positive terminal of the battery, and then the black wire to the negative terminal. Proceed with step 3.

Step 3: Turn the ignition lock to the “Start” position and start the engine, keep it going for about 4 to 5 seconds.Read the voltage as shown on the battery multimeter while starting the engine.The battery is in order if the multimeter reading exceeds 9.5 volts during start-up. A reading of less than 9.5 volts indicates too high a drop in voltage. The cause may lie in a poor chemistry transfer in the battery itself due to age. About time to replace it! Battery in order? Keep on reading.

2. Weak starter.

Since the battery has found to be in order or replaced, it is now time to have a look at the starter motor. Even though the battery was the only problem, the following test may prevent many headaches in the future. Corrosion is a common problem. Check the connections from the battery to the starter itself for any deposits, including the negative terminal. Also check the condition of the connection between the starter and the engine block. This includes disassembly and inspection, but taking measurements could be a faster option in this case. This can be done as follows:

Step 1: Put the multimeter on Direct Current. Connect the red probe to the positive battery terminal and then on the relay connection of the starter, from where the copper cable enters the starter motor. This is the last connection before the + plus disappears in the starter motor itself. Below called the “M terminal”.

Step 2: Turn the ignition lock to the “Start” position and start the engine without running it. Read the voltage as shown on the multimeter while starting.

Step 3: Without drop in voltage between the cable and the starter relay, you should now read 0 volt. But people often read 0.1 volt, and 0.1 to 0.2 volt is no exception for older systems.

It means a voltage of e.g. 12.1 volts starts from the battery, but – due to resistance or a poor contact – ends up at only 12.0 volts. A multimeter measures the voltage difference.So the multimeter will measure a “difference” of 0.1 volt, any number higher than 0 volt indicates resistance. This process can be repeated on the plus terminal for each individual contact and connection, as well as for the negative terminal. That is because every positive electrically charged atom that goes in has to come out again via the negative terminal.

Step 4: Add up the values of the measurements in the previous steps. The sum of these values should not exceed 0 to 0.3 volt. The lower the number, the better it is. Just think of it. When starting an ordinary 4-cylinder boat engine, it will run up to 1000 Amps for a short period of time from standstill, after which it will drop until the engine runs at about 200 to 300 Amps. Until the engine runs 1000 Amps with 0.3 drop in voltage, the starter motor will drop 300 Watts. For a standard nominal 1200-Watt starter motor, it means that 25% of the starter capacity is lost. It shows that a minor drop may have major consequences. (example)

3. Conlusion.

First fix the resistance loss and then check that the power of your starter motor is back.
This was about testing the power supply of your starter system. If the starter motor still fails to give full power, it may have an internal defect. In that case, we suggest that you contact one of our specialists for more information about a possible solution.

Facts!

R = U / I or Resistance = Voltage / Current or Ohm = Volt / Ampere (Ohm’s law)

P = I * U or Power = Current * Voltage or Watt = Ampere * Volt

Watt = Ampere22 * Ohm
Watt = Volt / Ohm
Ampere = Watt / Volt
Volt = Watt / Ampere

An example with water flowing through a tube gives a better insight into the difference between current and voltage:

Electric charge in volts:pressure of the water in a tube.
Current intensity in Amperes:amount of water per second flowing through a tube.
Resistance in Ohm: thickness of the water tube.
Power in Watt:force of the water against e.g. a paddle wheel.

Click here to read more about replacing the starter motor

Replacing a starter motor yourself? In 3 steps.

Posted on 10 November 201916 February 2026 by abmarineservice — 1 Comment

Why separate electrical systems on board?

How can I properly manage my electrical systems on board?

It’s a comforting thought to have no hassle with the electrical systems on board. How do you ensure that the fridge is cold, the (boat) lighting works, and that you can still start the engine? A battery isolator might be the solution for you.

Charge both the start and lighting battery with a battery isolator (battery separator)

Do you know the sound of a refusing starter motor due to low voltage? Perhaps the lighting, fridge, and other energy consumers have drained the power, and now you can’t start the engine. We recommend a separate lighting and start battery system, such as the Victron Battery Isolator.

Why separate electrical systems on board?

The required power for the lighting system and the starting system differ. The lighting system is often used for long periods, while the starting system only demands high power for short durations. The best solution for this issue is to use two different batteries that are tailored for each system. Fortunately, start and traction batteries are available on the market.

Always a charged battery

Even for a small setup, using a separate lighting and start battery system is advisable. While using power from the lighting battery, there is no connection to the start battery, keeping it full and available for engine starting.

Separate power sources can still be charged with the engine’s alternator

When you separate both power sources, you need to be able to charge them separately. If you want to separate both batteries but still charge them with the engine’s alternator, you use a battery isolator, also known as a diode bridge. The isolator distributes the voltage to both batteries. There are also distributors and separation relays available that switch to the other battery when one is full.

What is a battery isolator?

A battery isolator is a specially designed diode bridge, which connects the second battery (the lighting battery) to the alternator when the engine is running. The relay is controlled by the so-called “D+” connection from the alternator and has a provision to prevent overloading of the alternator and the voltage regulator.

Advantages of a battery isolator

The main advantage of a battery isolator is that there is an absolute separation between the battery sets under all circumstances. If one of the two batteries is empty, it can never transfer the power. Think of two barrels of water. A battery isolator conducts the charging current from the alternator or battery charger and distributes it to both battery sets. This is done through two or more diodes, which act as a “check valve” for the charging current. There is only one direction for the current, and it cannot flow back. We offer a range of simple battery isolators to realize the above system. Always check the voltage and required power that can go through the relay.

NB: You can also charge the battery with a battery isolator from the regular 230V power grid.

How many volts per relay?

The rule of thumb is as follows:

70 AMPERE DIODE BRIDGE: for battery chargers and alternators up to 55 Ampere maximum charging current.
120 AMPERE DIODE BRIDGE: for battery chargers and alternators from 60 to 90 Ampere.
150 AMPERE DIODE BRIDGE: for battery chargers and alternators from 100 to 120 Ampere

Battery isolator with compensation diode

Note that a diode always has a bridging voltage (threshold voltage) of 0.6 volts. This means that with a 14V charging system, a maximum of 13.4V will go to the battery. This can be a problem with older types of alternators. An isolator with a compensation diode prevents voltage drop across the diode, ensuring the battery is charged with the correct voltage.

Setup of a battery isolator

See the diagram for a simple setup of a battery isolator:

Buy a battery isolator (battery separator)

Click for a affordable battery isolator for your boat!

Posted on 8 November 201921 January 2026 by abmarineservice — 5 Comments

A dry or wet exhaust?

What is better, a dry or wet exhaust?

A dry exhaust is a simpler system than a wet exhaust. However, the wet exhaust does have significant advantages. Which will you choose? In this article, we’ll guide you through this dilemma, explaining the difference between a dry and wet exhaust, and outlining the various types of cooling water systems. Shall we dive in?

What is a dry exhaust?

A dry exhaust system is similar to a car’s exhaust. A pipe is connected to the exhaust manifold via a flexible joint and directs exhaust gases directly outside through the silencer. The engine’s cooling water is added to the exhaust system externally, or much later on.

The pipes and tubes are often made of steel to prevent them from melting due to the heat. It is a simple system, but has two major drawbacks:

it gives off a lot of heat (up to 600 degrees at the source) and the system produces a lot of noise.
A dry silencer is often desirable to dampen the noise.

Right, now that we know what a dry exhaust system is, let’s move on to the next issue.

What is a wet exhaust?

With a water-cooled exhaust (wet exhaust), the manifold is fitted to the engine. The manifold is often custom-made and cast iron. A wet exhaust can also often be recognised by the frost plugs in the cooling channels. The heated cooling water in the engine is around 60 to 90 degrees when it leaves the engine and can therefore still be perfectly used to cool hot exhaust gases of 600 degrees.

In the initial section of the exhaust, the water and gases are not yet mixed. This prevents water from entering the engine and impeding the gases. The gases must be able to exit the engine smoothly to avoid reducing engine performance. Shortly after the engine, the gases and liquids combine and exit the engine via the exhaust.

Differences between a wet and dry exhaust

The main differences between a dry and a wet exhaust are the temperature and the noise. A dry exhaust is louder than a wet exhaust, and the temperature of a dry exhaust system is higher than that of a wet exhaust. The difference in temperature between a dry and wet exhaust is quite noticeable. With a wet exhaust, the noise is muffled by the water. A rubber exhaust hose then offers greater flexibility and immediately increases the lifespan of the exhaust.

With a lower-mounted engine, as is common on many yachts, good water drainage is especially important. The hull of the boat can indeed influence the placement of the exhaust and the functioning of the system.

The different types of cooling water systems

There are three types of cooling systems:

Direct cooling of the boat: A cooling water system in which the engine block is pumped with canal water via a rubber impeller pump.
Indirect cooling of the boat: a separate cooling water system (also called an intercooling or heat exchanger system) in which you have coolant in the engine and pump cooling water through a heat exchanger using an impeller pump.
Indirect cooling of the boat: a keel cooling system, where cooling pipes filled with coolant run under the boat. The latter system does not allow for a wet exhaust, unless an additional impeller pump or electric pump is fitted.

Converting a dry exhaust to a wet exhaust system

If you want to experience the benefits of a wet exhaust system, you can convert your dry exhaust. Complete exhaust sections are available. Alternatively, you can opt to add water to your existing dry exhaust system, with only the initial section remaining uncooled. While the conversion may require an investment, it’s a job that a competent DIYer can manage with great satisfaction.

Wet exhaust system with waterlock and silencer

A wet exhaust system comprises the following components (from start to finish)

A water intake pipe under the boat with a shut-off valve to stop the supply for repair or maintenance.
A seaweed filter as an inline filter to prevent any harmful material from reaching the impeller pump.
A suction pump on the engine (impeller or raw water pump).
If converting from keel cooling to indirect cooling: a heat exchanger with a water-cooled exhaust manifold.
A water injection fitting, fitted after the exhaust manifold, which adds cooling water with an aerator to prevent the water from siphoning back into the engine when the engine stops.

The use of a so-called waterlock is recommended for a wet exhaust. It collects the water and uses overpressure to push the water up through the exhaust with the exhaust gases. The waterlock also dampens sound by impacting the water.

The goose neck acts as an extra safeguard to prevent water backing up when the engine is positioned lower, as is the case in most sailboats.

The silencer can still be fitted as an additional option; view our options in the category exhaust damping.

With wet exhaust systems, you can also use a muffling and flexible exhaust hose. The whole thing is securely fastened with stainless steel hose clamps.

Would you like advice about the exhaust system? Get in touch via the contact page.

Posted on 8 November 201916 February 2026 by abmarineservice — Leave a comment

A flexible engine mount, constant velocity joint?

How can my boat be quieter and my sailing more relaxed?

Have you ever enjoyed a nice boat trip but then had to turn the throttle back because of the noise? For relaxation, you want to be able to hear each other, right? Consider a flexible engine mount.

A flexible engine mount

With a flexible engine mount, you use engine supports. These supports reduce noise and vibrations as much as possible.

Sailing without vibration

What is the key to sailing without (too much) vibration and having a relaxing sail? The principle is simple. You remove the rigid connection between the engine and the foundation. This transmits the vibrations from the engine. Let the engine float on its foundation, and the noise is gone. Start with the basics.

Why do engines vibrate?

Engines have internal components that move quickly back and forth. In milliseconds, the piston is forced down by an explosion and then pushed back up by the crankshaft at the same speed for a new compression stroke. With short piston strokes and aluminum engine blocks, modern engines are made compact and lightweight. This provides many advantages, such as space savings and lower production costs. A disadvantage is that vibrations are less dampened and absorbed due to the low weight. Also, the shorter engine stroke requires higher RPMs to stay running. As you know from experience, the more throttle you give, the more noise you get.

Loose support of the engine

That’s why it is important to ensure a good and solid foundation for the engine with soft engine supports. The supports essentially decouple the engine from the boat’s foundation. The best option is a soft enough engine support that is still strong enough to support the weight of the engine, reverse gear, and part of the propeller shaft.

As soft as possible rubber

The softness of rubber is expressed in SHORE with a number for hardness. Additionally, the letter A to D determines in which category the rubber belongs. Rubber with a SHORE of 10 is very soft, and above that, it becomes firmer. A heavier engine requires firmer rubber to ensure that the rubber isn’t pressed out by the weight. Engine supports usually start at 35 SHORE. Look for rubber that is soft enough, but still firm enough to support the engine. The softness and quality of the rubber often determine the final price and durability.

Don’t skimp on the price of good engine supports. Cheaper engine supports, like washing machine mounts, sometimes work well but aren’t always resistant to oil, grease, and diesel fumes in the engine compartment.

Too soft?

With too soft engine supports, the strength is lost in the pull and thrust motion made by the propeller shaft and engine during maneuvering. You can choose V-engine supports, which lock the engine in place under load with their V-shape. However, this does reduce damping because the engine pushes against the rubber.

So what is the optimal engine mount?

Do you want optimal damping? A combination of flat vibration dampers with a thrust/bearing is the best solution. A thrust/bearing keeps the propeller shaft in place. It is a bearing that absorbs forces from all directions. This is also suspended in rubbers and mounted between the reverse gear and the propeller shaft. After installation, it must be precisely aligned to prevent overload of the bearings and shaft seals. Even better is placing a flexible (homokinetic) coupling between the coupling and shaft, allowing all parts to continue rotating without stress, even under load and possible shifting.

Example setup of a homokinetic engine mount

Advice for less vibration while sailing

Looking for less vibration and more relaxation? Or a better engine setup? Take a close look at the foundation of the engine setup. Can this be improved? Feel free to consult with our specialists. Each engine and coupling brand requires its own force calculations. Based on this data, we can develop a plan for you.
As preparation, we’d like the following details:

– Brand and type
– Maximum RPM
– Number of cylinders
– Engine weight
– Thrust bearing installed

AB Marine Service provides setups for any brand, type of engine, and reverse gear. Request your own relaxing sail today.

Posted on 8 November 201916 February 2026 by abmarineservice — Leave a comment

Slime strings and clogged fuel filters.

Slime strands & clogged fuel filters. Diesel bacteria; for those who are unfamiliar, we can say that prevention is better than cure. Those who have experienced it will not forget it quickly. In no time, clogged fuel filters or even complete pipes and pumps stopping due to long black flakes and brown strands. That’s the end of your trip. Diesel bacteria are comparable to algae in an aquarium. They mainly form on the bottom layer of water and diesel in the tank. Water is heavier than most fuels and will collect at the bottom of your tank. Because the suction or draining point of the fuel pump is often located higher, the water can remain in the tank for a long time. Bacteria in the diesel? Diesel, like many fuels, is a natural product and contains microbes. With the right preservation and treatment, you will have little to no trouble with bacterial growth. However, give them the right breeding ground, like water, and they multiply at a rapid pace. The bacteria are always present in the fuel but also in the outside air and can enter the tank through the vent. Condensation and oxygen from the outside, combined with a poorly functioning water separator, make the fuel tank the perfect breeding ground. Especially in watersports, the circulation rate of the fuel tank is not always very high. Condensation as a breeding ground A fuel tank is often installed inside. In the evening, the tank cools down and warms up again during the day. The oxygen that moves through the warming and cooling process always contains moisture. Warm air that cools down forms water droplets (rain), and this condenses against the walls of the tank. This water drips down and settles at the bottom of the tank, below the diesel. Diesel has a lower specific gravity than water. A practical tip is to keep the space above the fuel as limited as possible. Always fill the tank completely before leaving the boat unused for a long time (for winter storage with winter diesel). After all, the less space there is at the top of the tank where oxygen and condensation can settle on the walls of the tank, the better. Warm and moist conditions are also perfect for diesel bacteria to grow rapidly, but even during winter, diesel bacteria can thrive. A clean and dry tank vent in the right place is therefore recommended. Rain and wave action Even incorrect placement of, for example, the fuel fill or vent can quickly cause water accumulation in the tank. Rainwater that can seep in through an external vent, or splashes of waves hitting the deck, can get into your tank, so this needs to be taken into account. Also, pay attention to a proper seal of the diesel fill cap on the outside and periodically check the seals in the cap. Is this new? Diesel today must contain less sulfur than in the past, as required by the government. Sulfur that you burn is highly polluting for the environment, but sulfur used to prevent bacterial growth in the past. In addition, a few percent of biodiesel is now added to diesel. Biodiesel is made from plant-based products and is therefore interesting as the world’s oil reserves are depleting. But biodiesel has the property of quickly attracting water and contains a higher percentage of microbes. What can you do? If possible, check visually if you can see water formation in the tank, often you’ll see a large “bubble” of water at the bottom. If you have never checked or drained it, that’s a good start. Do you frequently encounter this problem? Look at what the cause might be, as described above, such as malfunctioning venting, etc. The fuel supply pump that delivers fuel to the engine also often pumps the diesel back into the tank several times through the return line. This way, your tank is often kept clean and filtered. A proper filter installation with a water separator can catch water from your tank. Since water is heavier than diesel, it is collected at the bottom of the glass. Through the glass, you can also see whether your diesel is clean or maybe cloudy, which indicates contamination. Do you experience a lot of contamination and have trouble draining the tank? Then you can opt for an external pumping system that continuously circulates the diesel through a filter set and separates the water. Fuel Filter Water Separator Fuel Pump Hoses and Pipes

Comments or experiences are welcome!

Posted on 8 November 201916 February 2026 by abmarineservice — 5 Comments